Telephone system



Oct. 28, 1941. R' EI HERSEY 260,524

TELEPHONE SYSTEM :usr rows /NVEA/ro@ Ef HERSEV BV www? A TTnD Ek Oct.28, 1941. R. E. HERsEY 2,260,524

TELEPHONE SYSTEM Filed June 4, 1957 2A Sheecs--Sheer1 2 FIG. 2

\ II/00 A Faun/zen l I l: I

` A Top/v y Patented Oct. 28, 1941 TELEPHONE SYSTEM Ralph E. Hersey,

Telephone Madison, N. J., assigner to Bell Laboratories, Incorporated,New

York, N. Y., a corporation of New York Application June 4, 1937, SerialNo. 146,356

(C1. 17eisi 8 Claims.

The invention relates to telephone systems and particularly toimprovements in signaling arrangements for such systems.

An object of the invention is to simplify and reduce the cost of theequipments for ringing subscribers on called'lines.

Another object of the invention is to provide ringing means that doesnot require the usual ringing currentl supply nor ringing trippingequipment at the central oiiice.

the circuits for ringing the bell will not function as'the talkingbattery connections have previously been reversed and are maintainedreversed until the connection is released at the central office. Thenormal battery andV ground connections for a subscribers line throughthe usual line relay is of such polarity that the subscribers bellHeretofore systems have been provided in 1 which ringing current appliedat the central office causes the operation of ringing apparatus at asubscribers station and when the subscriber answers the call by removinghis receiver from the switchhook, ra tripping relay at the central foffice is operated to discontinue the application of ringing current. Incertain systems, for example in case of party line `selective ringingsystems, cold cathode gas-filled tubes of the trigger type have beenscribers telephone sets. In these latter systems, a tube breaks down inresponse to ringing current to close a connection for a ringing circuitto ring a particular bell depending on the method of Wiring. l

A feature of the present invention is to provide a ringing and trippingarrangement for substation signaling in which the usual machine ringingequipment at the central oflice is eliminated and whereby a bell at thesubstation may be rung merely by closing the connection for thesubscribers line from the talking battery 'at the central office.

It is a special feature of the applicants invention to employ agas-filled tube at the substation for this purpose. This tube is inseriesvwith a bell winding and a resistance, and the tube and bellwinding are shunted by a condenser. When a connection is established atthe central cnice to thissubstation, the usual talking battery isapplied on the line and the condenser is thereby charged until the tubebreaks down, at which time the condenser discharges through the bellwinding operating the bell, and the tube is then restored :to normal.The condenser is then again charged and these operations are repeated.The bell will therefore be tapped intermittently at intervals dependingon the characteristics of the condenser and ithe breakdown potential ofthe tube. When the subscriber answers by removing his receiver from theswitchhook, the circuits for the bell and resistance are madeinoperative. The arrangement is such that when the called subscriberrestores his receiver on the switchhook used in the various subwill notring. lThe discharge tube is for these purposes polarized lto operate oncurrents in one direction only.

The-invention has been illustrated in 'the a'ccompanying drawings inwhich:

Fig. 1 shows the invention applied to an automatic step-by-steptelephone system; and

Fig. 2 shows it applied to a manual telephone system.

Reference is now made to the drawings and particularly' to Fig. l, inwhich as much as 'is necessary to illustrateV applicants invention hasbeen shown of an automatic step-by-step-system. Any standard automaticsystem may be employed using a connector such as is illustrated at C inthis drawing'lwith the usual ringing source and tripping relayarrangement eliminated and otherwise arranged in accordance with theapplicants invention. A calling subscribers line has been shown indiagrammatic form at l terminating in a line inder LF connected throughany number of intermediate switches and a selector S having access tothe connector C. This connector in turn `has access to a subscribersline 3 terminating in afcalled subscribers substation apparatus 4arranged in accordance with the applicants invention.

A description will now be made of the operations When the substation 4is called from the calling subscribers line l. The calling subscriber atI may connect throughthe line nder LF and intermediate switches toselector S which then finds the connector C in any manner well known instandard step-by-step systems. When the connector C has been found andconnected to, a circuit is completed over the tip and ring conductorsfor the operation of relay 5 from battery and ground through thewindings of this net 8 and relay 9 from battery through the Winding ofthis magnet, winding of relay .9, vertical off-normal contacts VON,contacts of relays 1 and 5 to ground. This causes the vertical magnet 8to operate the connector switch C to take one vertical step. On thesecond release of relay 5, the circuit for the vertical magnet extendsthrough thevfertical off-normal contacts VON and the armature and frontcontact of relay 9, which remains operated during the sending of theimpulses of this digit, and the vertical magnet is operated to thedesired `level depending on the number of pulses received. At

the end of this series of impulses relay.9,1 which Y.

is slow to release and remains operated# during this series of impulses,will release and' on the first impulse of the unit digit, a circuitvwill be Y completed for the rotary ymagnet I fron'bat# tery through thewinding of this magnet; con` tacts of relays II, I2 land .9 andthevertical off-normal contacts IVON, contacts offrelays I and to ground.It Vshould be noted that' a cirf cuitis also completed for relay I3from'battery through the winding of this relay to ground at relay 5 overcontacts of relays VI2 and 9,'contacts VON-and contacts of relays. 'Iand 5. Relay I 3V operates alocking circuit for itself through its lowerinner armature and vfront contact, to re` I9, contacts of the switchhook20, resistance 2l, condenser I8, over the tip conductor, contacts ofrelays II and Il, lower winding of relay 6 to ground. The condenser I8is lcharged in ac cordance with the potential of the battery through thewindings of relay 6 and at a speed depending on the characteristics ofthe condenser and the resistance 2'I. .When charged to a value sucientto break down the gas-filled tube 22, the condenser will discharge overa pathy from the lower side of the condenser I8, winding of the tap bell23, tube 22, to the upper side The tap bell 23 will operate of thecondenser. to actuate its plunger to give a single tap to its gong. Thetube will then be restored to normal and the condenser I8 will again becharged by the battery and ground through the windings of relay 6 andwhen suiciently charged cause lay 5 independent of the" contacts ofrelay I2.

Relay I3 is slow in releasing and remains oper-j ated during the dialingof the unit digit.l The rotaryrmagnet now advances the connector to, thedesired subscribers line, in this case line 3.

If the -line is busy, there is a ground'on the sleeve terminal whichwould cause the oper-ation ,l of relay I2 before relay I3 releases overa circuit from battery through the winding of relay I2, contacts ofrelays II and I3, over the sleeve circuit to ground. Relay I2 is lockedin oper` ated position on the release of relay I3 from battery throughthe winding of yrelay I2, contacts` of relay II make-beforefbreakcontacts of relay I3, contacts of relay I2 to ground at the` sleeve fromthe selector S, as is well known. Re-

lay I2 appliesbusy tone from the source I5 over` the tip conductor back`to the calling` 'subscribers line at I.

vIn case, h'wever, Vthat `the 'called line -is idle, relay I3 willrelease afteran interval and a circuit will be -completed for theoperation of Are- `I lay II from battery,` through the cut-off relay I6over the sleeve circuit, contacts of relay I3,

upper winding of relay II,l contacts of relay I 2 to ground over thesleeve circuit 4from the selector s. Reny is now lockedthrough itsiowerwinding from battery through the rotary mag,-A

net I0, lower winding of relay II, its lower outer armature and frontcontact to` ground at contacts of relay 'I thus. putting ,the releaseof,this

connection undery control of the calling 5 subscribers line. ing ofrelay II prevents the operation of the 3 rotary magnet I0 at this time.3 erating provides a ground for the sleeve `circuit .y and cut-off relayI6 and is held operated by this 1 ground overthe sleeve. Relay I Ialsocloses at its two upper armatures and front contacts a 1 connectionfor thev tip and ring conductors to the called linev 3 from battery andground 3 through the windings of -relay 6 and contacts of g relay I 1. jcharged over a circuit from battery through the 1 upper Windingof relay6,-' contacts of j relays'II 1 and vIIr over theV ring'conductorthroughl the the right-hand winding of the repeating coil The resistanceofthe lower wind.-

Relayl `I I in opthe tube 22 to `again break down to operate the tapbell 23 a second time. These operations are continued at afrequencyAdetermined' bythe characteristics 'of the resistance 2| and 'condenserI8and thebreakdown characteristics of the tube 22.'` The tap bel1'23/will therefore continue tc ring its gong until the. subscriber answersby removing his receiverfrom the .switchhoolL In doing' this 'thecharging 'circuit' through resistance '2| for the condenser I8 is openedand the rcondenser is short-circuited through the transmitter. and"consequently the ringinghwill cease. When the called subscriber atstation 4 answers, rrelay 6 will' operatel and "reverse the battery andground through the winding ofre lay 5over"the tip4 and ringconductorsftofthe callingv subscribers line yas a supervisoryzsignal andtalkingl battery is now supplied for the calling subscribers linethrough the Winding lof, relay 5 and for the' called subscribers linethrough the winding of relayf.6 and the talking connectionovercondensers 25 and 26." f

When relay 6 operates it closes an obvious circuit'for relay I1 whichinoperating locks itself to. groundv at relaylII and reverses the batteryand ground connection over th'elwindingl of relay 6 for the. tip andring conductors through the called line loop. ,y The gas-filled tubev 22is "po larized and will not break down withbattery a'nd ground reversed.TheV tap bell is therefore preventedfrom ringing whenthe calledsubscriber replaces his rreceiver on the switchhook.- The callingsubscriber when releasinghcauses.the re; leasof relay 5 which inturnreleases'relaysl, II, Il and I6. "A circuitv is then closed'ffor 'reflease magnet 2 from battery windingl of this magnetV contact VON,contacts of relaysv II",- .1 andh5,t o ground. It should'be noted'th'atwhe relay `II releases the connectionV to v'the .substation frombattery' and ground'over relay 6 is opened 'so relay I'I'may thereforebe released to restore the polarity of the battery and ground to the tipand ring conductors vfor the next call.y The polarity `of the batteryand ground through' line|64. In establishing this connection by 'intserting the plug H35 in the jackv I06,a circuit-is completed forthe-'condenser lIIl'I from battery through-*the lower right-hand windingof the repeating coil |08, winding of the supervisory ofthe repeatingcoil |08to ground. This causes the `condenser |`|to be charged and whensufficiently charged it causes the tube ||4 to break ldown through thewinding of the tap bell ||5 which taps `its gong once. These operationsare then repeated until the ,subscriber at this stal tionanswersfwhenithe ringing ceases and the talking circuit is completed. Itshould be observed that when the subscriber answered the supervisoryrelay |09 operates as'usual to extinguish the lamp I0 which lighted inthe usual manner, when plug |05 was inserted in jack |06 over the sleevecircuit which circuitv also caused the operation of the cut-oli relay Itshould further be observed that the original circuit for lamp ||6extends through the left-hand winding of relay ||0. This, however, didnot cause relay ||0 to operate. On the other hand, when relay |00operates, the shunting' circuit for lamp ||6 extinguishes the lamp andnow extends through both windings of relay ||0 causing this relay tooperate, The operation of relay ||0 opens the ring conductor but by thattime the operation of relay |09 has already provided a substituteconnection for this conductor so at this time no disconnection takesplace. However, when the subscriber at |03 replaces his receiver relay|09 releases which opens the ring conductor and consequently preventsbattery and ground through the right-hand windings of the repeating coil|08 from charging the condenser |01 and start ringing of the bell ||5 atthis time, as relay ||0 will be maintained operated over the sleevecircuit, through its left-hand winding to prevent the ring conductorfrom being closed by the contacts of this relay. The characteristics ofrelay ||0 are such that it will not operate on current thro-ugh itsleft-hand winding, but after once operated by current through bothwindings, current through the left-hand winding will maintain itsoperated. The supervisory lamp ||6 now lights as a disconnect signal andthe operator removes the plug |05 from jack |00, whereupon relays ||0and are released and lamp ||6 extinguished. Relay restores theconnection for the line |04 to battery and ground, through the windingsof the line relay but the polarity of the battery and ground connectionfor this relay is such that the tube ||4 will not operate.

What is claimed is:

1. In a telephone system, a central oflice, a subscribers station, aline connecting said ofce and station, a source of talking currentconnecti able to said line at said central office, a ringer at saidstation having a winding and circuit means at said station including agasi"1lled discharge tube connected to said winding and operative inresponse to the continuous iiow of current from s aid source over saidline for producing an intermittent current through said winding for tilecorresponding intermittent operation of said ringer.

2. In a telephone system, a central office, a subscribers station, aline connecting said ofice and station, a source of talking currentconnectable to said line at said central oflice, a ringer having awinding at said station, circuit means at said station connected to saidwinding and said line and including a network and a gaslled dischargetube operative in response to the continuous ow of current from saidsource when said source is connected to the line for producing anintermittent current through said winding to operate the ringer` atintervals.

3. In a telephone system, a central oiice, a subscribers station, a lineconnecting said oiiice and station, a source of talking currentconnectable to said line at said central oice, a condenser and aresistance in a series connection in said line at said station, agas-filled discharge tube having a denite breakdown potential and -a.direct current ringer in a circuit in vshunt of said condenser, saidcondenser, resistance, tube and ringer being so adjusted that on theconnection of the talking battery to the line at the central ofce thetube is caused to discharge at intervals for the operation of the ringeronce for each discharge.

4. In a telephone system, a central oflice, a subscribers station, aline connecting said oflice and station, a source of talking currentconnectable to said line at said central oice, a condenser and aresistance in a series connection in said line at said station, agas-lled discharge tube having a definite breakdown potential and adirect current ringer in a circuit in shunt of said condenser, saidcondenser, resistance, tube and ringer being so adjusted that on theconnection of the talking battery to the line at the central onice thetube is caused to discharge at intervals for the operation of the ringeronce for each discharge, and means for disabling the circuit for thedischarge tube in response to the subscriber removing his receiver fromits switchhook.

5. In a telephone system, a central oiiice, a subscribers station, aline connecting said office and station, a source of talking currentconnectable to said line at said central ofiice, a

condenser and a resistance in a series connection in said line at saidstation, a gas-lled discharge tube having a definite breakdown potentialand a direct current ringer in a circuit in shunt of said condenser,said condenser, resistance, tube and ringer being so adjusted that onthe connection of the talking battery to the line at the central officethe tube is caused to discharge at intervals for the operation of theringer once for each discharge, and means responsive to the subscriberremoving his receiver from its switchhook for opening the connection forthe resistance and short-circuiting the discharge tube, the ringer andthe condenser.

6. In a telephone system, a central cnice, a subscribers station, a linecomprising two line conductors connecting said office and station, asource of talking current connectable to said line at said centraloflice, a ringer at said station comprising a winding, a plunger and agong, the plunger being operated to strike the gong each time thewinding is energized, a gasiilled discharge tube, and a condenser atsaid station, a circuit means for normally connecting said winding andsaid discharge tube in series across the two conductorsA of said lineand the condenser in shunt of said winding and discharge tube, saidwinding, tube and condenser being responsive to continuous now o currentfrom said source for alternately charging the condenser and dischargingit across said tube in said winding to energize said winding tointermittently operate the armature to strike the gong.

'7. In a telephone system, a central oflice, a subscribers station, aline connecting said oflice and station, a sourcev of talking currentconnectablevto said line at said central office, a ringer comprising agong, an armature and an operatingv Winding, Va condenser'charged inresponsefto the continuousflowof current in said line, and meanseffective at intervals for discharging said condenser through saidWinding -to deliver thereto impulses of current to operate saidarmature. t

8. In a telephone system, a central cnice, a telephone station, a linevconnecting said cen- .tral oice andstation,Y a. source of direct fcurtrent connectalole to said line at said central oflo said signaldevice for each measured interval.

RALPH E. HERSEY.

